172 NEW YORK STATE MUSEUM 



DESTRrCTIVE SUCKING INSECTS 



The work of sucking insects is easily distinguished from that of other 

 classes because in no case is tissue removed. Their operations are usually 

 followed by shrinking, discoloration, and decay. 



Key to destructive sucking insects 



Small, many with limited locomotive powers 



Leaves, species found on foliage only 



Yellowish green, lirown marked aphids or plant lice occurring in clusters on the 



underside of Norway maple Chaitophorus aceris, p. 174 



A pretty winged, red eyed, black and white marked plant louse, together with pale 

 yellowish, wingless young, may be found on the under surface of soft majile leaves, 

 specially on those near the tips 



Painted maple aphid, D r e p a n o s i p h u m a c e r i f o 1 i i, p. 175 

 A slight, inconspicuous plant louse on the underside of American elm leaves 



Elm leaf aphid, C a 1 1 i ]i t e r u s u 1 m i f o 1 i i, p. 176 

 Curled and gnarled leaves of \vhite elm in June, with whitish pellets of honeydew 

 dropping from the tree 



Woolly elm leaf aphid,_ S c h i z o n e u r a a m e r i c a n a, p. 177 

 Sugar maple leaves bearing numerous cottony masses protruding from under brownish 



scales Maple leaf scale, P u 1 v i n a r i a a c e r i c o 1 a, p. 179 



Cottony white insects on the under surface of sugar maple leaves and masses on the 



trunk Maple Phenacoccus, P h e n a c o c c u s a c e r i c o 1 a, p. 182 



American elm leaves deformed by a peculiar cockscomblike gall in June. 



Cockscomb elm gall, C o 1 o p h a u 1 m i c o 1 a , p. 186 

 Snow white, woolly plant lice on larch needles in May and June 



Woolly larch aphid, C h e r m e s s t r o b i 1 o b i u s, p. 187 

 Somewhat cone-shaped, many-celled galls at the base of young spruce shoots 



Spruce gall aphid, C h e r m e s a b i e t i s, p. 189 

 Small, yellowish white, jumping insects about '/lo inch long occur in swarms during 



midsummer, on rose leaves Rose leaf hopper, Typhlocyba r o s a e, p. 191 



Bark, aphids or plant lice and scale insects on limbs or trunk 



Species with more or less flocculent tnatter 



Clusters of white woolly substance on elms and trunks of white elm 



Woolly elm bark aphid, Schizoneura rileyi, p. 192 

 Patches of flocculent, downy matter on the smooth bark of white pine 



Pine bark aphid, Chermes pinicorticis, p. 192 



